Numerous applications utilize digital data storage and transmission for data communication, such as sending information via internet web sites or storing information on compact discs. Digital transmission systems or digital data storage systems typically use a sequence of binary information, either delivered to a receiver across a transmission channel or stored to a medium (e.g., CDROM). However, the binary information may become corrupted during storage or transmission, which could impair the accuracy of the information.
As a result, error control coding is often applied to the transmitted or stored data. Techniques known as forward error correction schemes have been developed to improve the reliability of the data communicated in digital applications. Forward error correction schemes are error control techniques that can detect and correct corrupt data without requiring the transmitter to re-send the information. An example of such a scheme is the Reed-Solomon code.
Many forward error correction schemes, such as the Reed-Solomon code, typically encode a group of data symbols into blocks of a predetermined size. For each block, an additional number of “parity” symbols are computed and added. The resulting augmented block is typically referred to as a “codeword.” Following transmission, or following reading of the stored data, a decoding technique is applied to the codeword to correct for errors that occurred during storage or transmission to thus restore the original data.
While such techniques have improved the reliability of transmitted digital data, further improvement is desireable. Despite the use of current error correction techniques, undetected errors may still occur, or errors may be detected but not properly corrected. This results in data that is less reliable than desired.